1. Field of the Invention
This invention relates generally to data transmission systems and more particularly to monitoring the accuracy of data transmitted over wireless or cable communication systems.
2. Description of Prior Art
As the uses of computers proliferates there is a growing need for remote terminals to communicate with computers and with computers to communicate with each other. In the checkless society envisioned for the future, for example, there will be a network of bank computers communicating with each other and with computers in the retail and industrial sector such that a transaction in a retail establishment thousands of miles from the customer's bank is immediately recorded via communicating computers. The account of the retail establishment is credited whereas the account of the customer is debited. Similarly a customer's credit may be instantaneously checked. Other uses of data communication too numerous to mention are not only envisioned but in some instances are presently operational.
In such a network of computers it can readily be appreciated that accuracy of the data transmitted is of utmost importance. Whereas some improvements in transmission of data have been made in order to insure that the data received is the same as the data transmitted, there is also a need to continuously monitor the transmit/receive communication system so that degradations or malfunctions in the system may be detected at an early stage in order to institute timely corrective action.
Typical monitoring means of prior art consists of apparatus which perform communication system assessment on an interfering basis which requires the transmit/receive communication system to be taken out of service. Other prior art apparatus conduct communication performance assessment in a presumptive manner by monitoring circuit parameters such as signal-to-noise ratio, phase distortion, signal level, etc., which are not direct measures of the data communication system performance. Still other prior art monitors performance of the communication system in such a manner which does not enable detection of degradations in the system prior to system malfunction.
What is needed is a means to monitor data communications systems in an in-service, non-interfering manner, which utilizes a direct measure of system performance such as data error rate and which can predict system malfunctions by determining degrading trends of system performance.